Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface showing a selection screen for selecting a virtual press plate and a décor including a ceramic-style virtual press plate and a ceramic-style décor; and,

FIG. 2 is a perspective view of the display screen or portion thereof with a graphical user interface of FIG. 1 showing a selection screen for selecting a virtual press plate and a décor including a ceramic-style virtual press plate and a ceramic-style décor.

The broken line showing of display screen, images, text, and other elements are included for the purpose of illustrating portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 